• The Korean Journal of Physiology
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• 제27권2호
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• pp.115-122
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• 1993

There is evidence that noradrenaline enhances spontaneous contractions dose-dependently in guinea-pig antral circular muscle. To investigate the mechanism of this excitatory action, slow waves and membrane currents were recorded using conventional microelectrode techniques in muscle strips and the whole cell patch clamp technique in isolated gastric myocytes. On recording slow waves, noradrenaline $(10^{-5}\;M)$ induced the hyperpolarization of the membrane potential, although the shape of the slow waves became tall and steep. Also, spike potentiaIs occurred at the peaks of slow waves. These changes were completely reversed by administration of phentolamine $(10^{-5}\;M),\;an\;{\alpha}-adrenoceptor$ blocker. Noradrenaline-induced hyperpolarization was blocked by apamin $(10^{-7}\;M)$, a blocker of a class of $Ca^{2+}\;-dependent\;K^+$ channels. To investigate the mechanisms for these effects, we performed whole cell patch clamp experiments. Norndrenaline increased voltage-dependent $Ca^{2+}$ currents in the whole range of test potentials. Noradrenaline also increased $Ca^{2+}\;-dependent\;K^+$\;currents, and this effects was abolished by apamin. These results suggest that the increase in amplitude and the generation of spike potentials on slow waves was caused by the activation of voltage-dependent $Ca^{2+}$ channel via adrenoceptors, and hyperpolarization of the membrane potential was mediated by activation of apamin-sensitive $Ca^{2+}\;-dependent\;K^+\;channels$.

• Applied Microscopy
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• 제33권4호
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• pp.291-298
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• 2003

스트레스는 교감신경계와 부신을 활성화시킨다. 본 연구에서는 고염식이가 흰 생쥐의 부신수질에 미치는 영향을 tyrosine hydroxylase (TH) 면역염색법과 투과 전자현미경을 이용한 미세구조적 관찰로 규명하였다. 1. 부신수질의 TH 면역반응은 고염식이 후 증가하였으며 특히 고염식이를 4주간 시행한 경우보다 4일간 시행한 흰 생쥐에서 더 강하게 관찰되었다. 2. TH 면역반응은 부신수질을 구성하는 세포들 중 노르아드레날린 세포의 세포질과 과립들에서 주로 나타났다. 3. 고염식이를 시행한 흰 생쥐 부신수질의 노르아드레날린 세포에서는 세포질 내에 비어있는 공간들, 분비과립이 팽대되어 과립 내 물질이 한 쪽으로 치우친 형태 및 손상된 미토콘드리아등의 특징들이 관찰되었다. 이와 같은 결과는 고염식이가 스트레스를 유발하는 요인이 될 수 있음을 시사해준다.

• The Korean Journal of Physiology
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• 제8권2호
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• pp.67-74
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• 1974

The object of this research is aimed to determine the activity of adenyl cyclase in both skeletal muscle sarcolemma and fat cell ghost of epididymal adipose tissue isolated from rats exposed to cold for various length of time in an attempt to evaluate whether the tissue sensitivity to catecholamine is increased when rats are exposed to cold for long periods of time Methods: a)Animals: Albino rats ranging in weight from 150 to 200 gm were used throughout this study. For experimental purposes, the rats are divided into two groups: experimental animals were place4 in a cold room at $4^{\circ}C$, controls being kept at $25^{\circ}C$. At the end of 2, 4, 6, 12, and 16 weeks. exposure to cold the rats were used to measure the adenyl cyclase activity. b) Isolation of plasma membrane from skeletal muscle and adipose tissue: The Plasma membrane of skeletal muscle from hind limbs of rats are prepared by the method employed by Rosenthal et at. and fat cell ghost of epididymal adipose tissue of rats by the method employed by Rodbell. c) Adenyl cyclase assay: Adenyl cyclase activity were measured by the method employed by Marinetti et al. Briefly, plasma membrane was incubated with $3^H-ATP$, various amount of noradrenaline and other incubation mixture at $37^{\circ}C$ for 20 minutes. After stopping the enzyme reaction by immersion in boiling water, carrier 3',5'-AMP was added to the system as a marker and $100\;{\mu}1$ aliquots of incubation mixture were pipetted on $20{\time}20$ Whatman No. 3 MM filter paper for one dimensional chromatography. The cyclic AMP spots were cut off and placed in counting vials containing 10ml of Bray's scintillation cocktail. Radioactivity was determined with a Packard Tri-Carb liquid scintillation counter. The enzyme activity is expressed as nanomoles of cyclic AMP produced per mg of membrane per hour. Result: 1. Average adenyl cyclase activity in the plasma membrane of skeletal muscle before and after noradrenaline administration was significantly higher in the cold-exposed rats as compared to the control. Continuous exposure to cold Produced an increased adenyl cyclase activity before and after noradrenaline administration. Adenyl cyclase activity reached peak levels at the 6 weeks exposure to told and level of adenyl cyclase activity remained high. Noradrenaline administration to the incubation medium induced a significant increase in adenyl cyclase activity and the degree of stimulation were proportional to the hormonal concentration But the rate of inclement in adenyl cyclase activity by noradreasline was the same in both groups. 2. Adenyl cyclase activity in fat cell ghost between cold exposed and control rats showed no significant differences before and after noradreualine administration. In summary, it can be concluded that cold adaptation give rise an increased activity of adenyl cyclase in plasma membrane of skeletal muscle in rats.

• The Korean Journal of Physiology and Pharmacology
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• 제7권1호
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• pp.47-52
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• 2003

The prostate gland contains numerous neuroendocrine cells that are believed to influence the function of the prostate gland. Our recent study demonstrated the expression of both ${\alpha}1$- and ${\alpha}2$-ARs, signaling the release of stored $Ca^{2+}$ and the inhibition of N-type $Ca^{2+}$ channels, respectively, in rat prostate neuroendocrine cells (RPNECs). In this study, the effects of NA on the resting membrane potential (RMP) of RPNECs were investigated using a whole-cell patch clamp method. Fresh RPNECs were dissociated from the ventral lobe of rat prostate and identified from its characteristic shape; round or oval shape with dark cytoplasm. Under zero-current clamp conditions with KCl pipette solution, the resting membrane potential (RMP) of RPNECs was between -35 mV and -85 mV. In those RPNECs with relatively hyperpolarized RMP (＜-60 mV), the application of noradrenaline (NA, $1{\mu}M$) depolarized the membrane to around -40 mV. In contrast, the RPNECs with relatively depolarized RMP (＞-45 mV) showed a transient hyperpolarization and subsequent fluctuation at around -40 mV on application of NA. Under voltage clamp conditions (holding voltage, -40 mV) with CsCl pipette solution, NA evoked a slight inward current (＜-20 pA). NA induced a sharp increase of cytosolic $Ca^{2+}$ concentration ($[Ca^{2+}]_c$), measured by the fura-2 fluorescence, and the voltage clamp study showed the presence of charybdotoxin-sensitive $Ca^{2+}$-activated $K^+$ currents. In summary, adrenergic stimulation induced either depolarization or hyperpolarization of RPNECs, depending on the initial level of RMP. The inward current evoked by NA and the $Ca^{2+}$-activated $K^+$ current might partly explain the depolarization and hyperpolarization, respectively.

• 대한한의학회지
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• 제19권1호
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• pp.392-409
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• 1998

The present experiment was designed to examine the effects of Jeongjihwan on carecholamines, serotonin, amino acids, lipid peroxide, free radical scavenging activity, malondialdehyde and superoxide dismutase activity in senile brain. It was performed by administering Jeongjihwan extracts of a variety of concentration to senile rats to experimentally determine effects of Jeongjihwan on biochemical changes in senile brain and examine protective effects against neurotoxin. To examine survival rate, the rat's spinal cord sensory ganglion cell pretreated in Jeongjihwan extracts was cultured in oxygen free radical. The results were summarized as follows: 1. Jeongjihwan significantly increased noradrenaline in the hippocampus and hypothalamus of the brain tissue of senile rats, and even though Jeongjihwan increased noradrenaline also in other brain tissue, there was no significance. 2. Jeongjihwan had no effects on dopamine changes in all brain tissue of senile rats. 3. Jeongjihwan significantly increased serotonin, but decreased in other brain tissue. 4. Jeongjihwan increased amino acid in the brain tissue of senile rats. 5. Jeongjihwan significantly decreased lipid peroxide and free radical in the brain tissue of senile rats. 6. Jeongjihwan significantly increased survival rate of nerve cell exposed to oxygen free radical. According to the above results, Jeongjihwan is assumed to improve brain function by reacting on biochemical changes of the senile brain and carries effects of protecting against neurocytotoxicity, and that Jeongjihwan can be used to treat regressive brain disease carrying symptoms of psychoactive disorders.

• Applied Microscopy
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• 제28권2호
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• pp.215-224
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• 1998

흰쥐 부신수질의 발생에 따른 미세구조적 변화를 관찰하기 위하여 임신 20일령, 출생직후, 출생후 7일, 15일 및 30일에 각각 조직을 채취하여 전자현미경적으로 관찰한 바, 흰쥐 부신 수질에서는 과립내용물의 전자밀도가 중등도 또는 낮고, 한계막에 싸여 있으며, 한계막과 과립 내용물간에 비교적 넓은 halo를 형성하거나 얇은 core를 형성하는 원형 내지 타원형의 소위 adrenaline 과립 $(123\sim200nm)$과 과립 내용물의 전자밀도가 adrenaline 과립보다 높고 한계막과 과립내용물간에 대체로 넓은 halo를 형성하는 부정형의 소위 noradrenaline 과립 (장경 $177\sim299nm$, 단경 $124\sim194nm$) 등 두 가지 형태의 과립이 관찰되었다. 이들 두 종류의 과립은 임신 후기 및 출생직후에서는 두종의 과립이 한 세포내에서 흔재하고 있었으나, 출생후 7일령에서부터 명확한 두종의 세포를 구별할 수 있었으며 과립의 크기와 수는 일령에 따라 다소 차이를 나타내었고, 핵내에서는 치밀체가 출현하였다.